A "journey" involving running in place in the deep end. Quite possibly I've gone off the deep end.

Wednesday, February 8, 2012

Ode to the Arc-Trainer

So, a few weeks back I had my silly shin tweak. I refuse to call it an injury, because in my mind, an injury is something that FORCES you to take time off. A tweak or a niggle is something where you don't NEED to take time off, but choose to do so, so as to avoid injury.

[yes, this distinction is being overly anal, but I do it for a reason. My big goal for this season is to avoid injury, and I don't want to put myself in a position where I don't back off because I don't want to admit something's wrong. If I call it a tweak when it starts, instead of denying it I respond immediately and prevent it from evolving into an injury. See how that works? You cut back by choice, before you have to.]

So, as I was saying, I tweaked my shin. And I cut back on my running and skipped my hard workouts for a month. And when I came back, I had really lost very little fitness. Pool-running was part of this, but I also give a great deal of credit to my use of the arc-trainer.

***

So what's an arc-trainer? Well, it looks like a variant of the elliptical, but with even less dignity. Here's a picture. It's a bit intimidating at first, but pretty easy to figure out how to get on (step onto the steps; grab the handles). Then once you get on, you program in time, incline, and resistance, and go on your way (well, so to speak).

So, it's like an elliptical, but different. I really don't know how to explain the difference, except to say that the arc-trainer at a low incline (I set on 3) has a motion that is much more like running than the elliptical. Same path traveled by the feet, same stride length, and same exact action of glutes versus quads. Below is a promotional marketing video from Cybex that hopefully sets this forth a bit better.

Particularly interesting is the point made about the excessive stress on the knee from the elliptical (versus the arc-trainer). From the video, it looks like the elliptical mimics the stride of an inefficient overstriding runner, while the arc-trainer's stride is much closer to correct running form -- thus the greater risk of hurting something while on the elliptical (this is likely why avid runners also cannot STAND the ellliptical). In my experience, the only real difference between the arc-trainer and the treadmill is that the former is non-impact, and so your calves and shins aren't doing the same work they would be doing while running -- fantastic if you're battling shin or calf issues.

To my mind, this makes the arc-trainer a better substitute for running than pool-running for both easy runs and tempos (more later on why intervals don't work as well). Pool-running tends to have a slightly different leg motion than land running, and also works the hip flexors far more than the glutes, leading to some imbalances when you return to land. Additionally, due to the effects of being in the water, pool-running heart-rates tend to be 15-20 beats lower than land, while the heart-rates one can achieve on the arc-trainer are nearly exact to those you hit while running. In fact, I simply equated arc-trainer miles to running miles by assessing how long I "ran" at a certain HR. 145-150 BPM for me is about 8:15 pace, so 32-33 minutes at that pace was ~ "4 miles"

As long as you're cleared for weight bearing, you can mimic close to the exact running motion by a) setting the incline to low and b) ignoring any handles that may exist and instead stabilizing your torso and swinging your arms as you would while running. It feels darn close to running (with the added benefit that you get to watch TV).

***

During my "tweak time", I used the arc-trainer to sub for easy runs, tempos, and the second part of long runs -- I just used perceived effort as my guide for how hard to go (upping the resistance to match), and a tempo on the arc-trainer felt nearly EXACTLY like a tempo on the track (and with nearly the same heart rate, to boot). For long runs, which my coach generally has us do as progressive effort workouts, I would do the first part of the long run by running easy outside for as far as I felt was safe. Then I'd drive immediately to the gym, hop on one of these, and after a quick warm-up I'd start pushing the effort to mimic the harder work of the final part of the long run.

By following this plan, I was able to keep up with my coach's scheduled workouts almost exactly. The one workout I DIDN'T use the arc-trainer for was intervals. For those, I relied on pool-running, simply because I found that the arc-trainer became unstable at the effort level I associate with hard intervals. Not enough that I thought it was going to flip over, but the machine would definitely start to move across the floor, creating a bit of a hazard.

***

So yeah, 4 weeks of substituting the arc-trainer for easy running and tempo effort, and pool-running for intervals, and I came back fine. Happy ending. But... there are two caveats about using the arc-trainer.

1) They can be hard to get access to. They're expensive and take up a good amount of floor space, so most of the gyms that have them just have a few. And, they are extremely popular for the silliest of reasons -- basically the calorie count on the machines is ridiculously inflated (supposedly I burn 1200 calories an hour on one of them) and so people desperately trying to match calories in versus calories out flock to them, because they "burn the most calories for the least effort...." (I leave it to the reader to assess the logic of that statement).

2) Because the arc-trainer is SO good at preserving every aspect of fitness except lower leg strength, there's a real risk that one gets reinjured by coming back to running too quickly. Your cardiovascular fitness is there, as is the quad and glute strength. But, if you've spent more than a week or so on one of these things, you've doubtless lost a lot of strength in your lower legs, and you need to carefully and gradually transition from the arc-trainer back to full time running to avoid a new injury (*ahem* tweak).

[Final disclaimer - I own no stock in Cybex, and have never had ANY communication with them regarding this or any other product. I just like the machine a lot]

Thanks for posting this review. I'm prone to shin "troubles" which is sufficiently vague as to not be an actual injury, but a good enough reason to avoid the sidewalks from time to time nonetheless. I think the Y has some of these, I'll give it a try next time I need to give my shins a rest.

This post = great. I tried the arc trainer when I was dealing with IT band issues last year and it was pretty painful for me at the time (while the elliptical was fine), but that makes some sense given what you said about it more accurately mimicking a running motion. The motion of running bothered me no matter in what form I was doing it, I guess.

Now that I'm dealing with my own shin...thing, I'll give it a shot again.

@Darkwave -- this is a general "thank you" for yourdeep water blog. My body is quite injury prone(I've never managed 40mpw without injury). I've beendoing land running followed by pool running for thelast 3 months and have become an believer!

Most runners I know aren't that supportive of d.w.r.so finding your blog was soooo valuable.

Nice! Those machines have always intimidated, so I use the elliptical for the same purposes of easy runs and tempo runs, paying close attention to HR. AND- I totally agree with your assessment of injury vs. tweak. If I am injured, I am kicking myself for not paying attention to my body. If I am tweaked and voluntarily taking time off, I am praising myself for my control.

Wanted to thank you for sharing your knowledge and experience on this blog. I've been injured a few times over the years while marathon training. The first couple injuries, I read your posts on pool running again and again. They were my only comfort while trying to stay fit in the same way, with coaches who really weren't into helping me adapt workouts to the pool. Now I'm in a new location without the same pool access, and so I've joined a gym where I can use the Arc Trainer, thanks again, in part, to you. You've made a difference. Just wanted to confirm that, in case you were skeptical. ;) Also, two questions: how do you do workouts on the Arc Trainer? Do you adjust the incline, resistance, or both? Or do you just move faster? And finally, did you find any correlation between spm on the Arc Trainer and while running? Looks like my spm count is a bit lower, but in the pool it was a LOT lower than when running. Thanks again for this blog!

I keep the incline low, and increase the resistance while keeping the same cadence. I think of it as similar to running, where you increase the pace by pushing off more forcefully with your legs - your cadence doesn't change that much.

I found my SPM to be considerably slower on Arc-trainer. About 140 per minute - I'm 180-190 when running.

I am not a runner. I have shin issues so I like the arc trainer at the gym because it doesn't hurt. That being said, I want to start a c25k program using the arc. How much faster should I go to simulate jogging vs walking on the arc?

'Love your "tweak" concept and have been doing that on an iliopsoas twinge that I'm trying to keep from flaring into my old nemesis, iliopsoas tendinitis. I only resort to pool running when I have shin splints - it's just too boring, I hate getting in and out of the pool in the winter (New England= locker rooms, hallways cold), and frankly, the swimmers at the gym pool don't like runners in their lane.

So, today it was the arc trainer. The other day was the Octane Fitness (kind of like an AMT without the up-and-down motion). How do you compare arc trainer "miles" vs. running miles? I've heard some use a 2/3 or 80% factor for ellipticals, and am curious what others do. Also, any thoughts on AMT for hips? I've read that one study from UW-LaCrosse about it not being so good for knees, but that's not my issue.

BTW, if you need any rationalization to avoid pool-running, I think pool-running places a LOT of stress on hip flexors - I would skip it if I was developing a psoas issue.

I would think the AMT would be OK for hips. I think the ultimate test is whether it works for you. Sorry that that's not a better answer, but I think sometimes it does depend on individual biomechanics.

Thanks. I got a heart monitor a few years ago, thinking it would change my life. But it turned out I was running exactly where I should be over these 30+ years LOL. So I figure the arc-trainer was like an easy run and I'd figure my "miles" accordingly. I agree on pool running also straining psoas (more rationalization - yea :-)).

Full slew of race reports here (from my first in June 2007 to 2010) and here (2011).

workouts

(you can click on the link to see the details)

Pool running conversion

I convert my pool-running into “mileage” with this formula:

1)10 minutes “easy” in the pool equals one mile

2)workouts translate by time into mileage, with the recoveries not counting for mileage.For example, I would normally cover half a mile in 3:00 during an interval workout, and 1.5 miles in 10:00 during a tempo.So 8x3:00 at interval effort is 4 miles, and 10 minutes at tempo effort is 1.5 miles.